Hydrometallurgical process

ABSTRACT

A process for winning nickel from source nickel values by reaction with carbon monoxide in the presence of cyanide ion catalyst. The reaction can be run as a solution or slurry of aqueous ammonia, optionally in a two-phase system with a waterimmiscible solvent for the nickel carbonyl formed. Associated metal values, such as copper and cobalt, are also separated and recovered by this process.

United States Patent [1 1 Colfield a al.

[111 3,804,614 1*Apr. 16, 1974 HYDROMETALLURGICAL PROCESS [75] Inventors: Thomas H. Coffield, Chaumont Gistous, Belgium; Kestutis A. Keblys, Southfield, Mich.

[7 3] Assignee: Ethyl Corporation, Richmond, Va.

[ Notice: The portion of the term of this patent subsequent to Dec. 18, 1990, has been disclaimed.

[22] Filed: July 27, 1971 21 Appl. No.: 166,642

Related U.S. Application Data [63] Continuation-impart of Ser. Nos. 807,987, March 17, 1969, abandoned, and Ser. No. 55,850, July 17, 1970, said Ser. No. 55,850, is a continuation-in-part of-Ser. No. 717,034, March 28, 1968, abandoned,

and Ser. No. 807,987.

[52] U.S. Cl 75/103, 75/101 BE, 75/119, 75/108, 75/117, 423/24, 423/32, 423/139, 423/141 [51] Int. Cl C22b 3/00 [58] Field of Search. 75/103, 119, 117; 23/203 C; 423/141, 139, 24, 32

[56] References Cited UNITED STATES PATENTS 10/1928 Muller et a1. 423/141 4/1951 Kincaid et a1 23/203 C Great Britain 23/203 C OTHER PUBLICATIONS Blanchard, Chemical Reviews," Vol. 21, 1937, pp. 3, 10-12.

Primary Examiner-Herbert T. Carter Attorney, Agent, or Firm-Donald L. Johnson; John F. Sieberth; James M. Pelt on [57] ABSTRACT A process for winning nickel from source nickel values by reaction with carbon monoxide in the presence of cyanide ion catalyst. The reaction can be run as a solution or slurry of aqueous ammonia, optionally in a two-phase system with a water-immiscible solvent for the nickel carbonyl formed. Associated metal values, such as copper and cobalt, are also separated and recovered by this process,

9 Claims, No Drawings HYDROMETALLURGICAL PROCESS CROSS-REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of applications Ser. No. 807,987, filed Mar. 17, 1969 now abandoned, and Ser. No. 55,850, filed July 17, 1970, which in turn is a continuation-in-part of applications Ser. No. 717,034, filed Mar. 28, 1968, now abandoned, and Ser. No. 807,987, filed Mar. 17, 1969 now abandoned.

BACKGROUND OF THE INVENTION The winning of metals, in particular, nickel, has been an important mark of the progress of civilizations. Nickel was isolated by Cronstedt in 1751. By 1804 the properties of the nickel were known with reasonable accuracy.

Referring to the section on copper in Kirk-Othmer Encyclopedia of Chemical Technology, second edition, volumn 6, page 131, and The Winning f Nickel, by Boldt, Jr., et al., D. Van Nostrand Co., New York, NY. (1967), the production of copper and nickel from ores are tedious, complex processes. Clearly, commerce could not bear the cost of such multi-step processes unless these metals were not so important. A detailed discussion of all ramifications of art-known methods for the production of copper and nickel would be out of place here. It is sufficient to relate the following facts.

Copper and nickel are both present in some ores worked today. Since 1899 nickel has been refined by the Mond process which comprises reacting nickel with carbon monoxide to form nickel carbonyl and subsequent decomposition of this product to carbon monoxide and nickel. In the section on nickel in Kirk-Othmer (supra), second edition, volumn 13, page 735 (739), there is described a hydrometallurgical refining process for nickel (practiced by Sherritt Gordon Mines Limited of Toronto, Canada). In this process, concentrates of pentlandite, (Ni, Fe) S are dissolved in an aerated ammoniacal solution. The nickel, copper, and cobalt sulfides dissolve as ammines, with iron remaining in the residue as hydratedferric oxide. Subsequently, copper is precipitated, and the remaining nickel solution is oxidized to form sulfate. The resultant solution is treated with hydrogen at 35 atms. and 190C to yield 99.9 percent nickel which is sintered into briquettes.

The Sherritt Gordon process is described in more detail in Boldt, .lr., (supra), page 299 ff. As described therein, the copper is removed from the ammoniacal solution by boiling off ammonia to precipitate cupric sulfide. The last traces of copper are removed by adding H 5. This must be done before nickel is precipitated with hydrogen, to avoid contamination of the nickel with copper.

Data on the reduction of copper (II) salts with carbon monoxide has been published; Byerley et al., Met. Soc. Conf., 24, 183 (1963); Chem. Abs., 64, 13441 h (1966). Conversion of aqueous nickel to nickel car bonyl has been disclosed in Chem. Abs. 53, 12606 e (1959).

In applicants previous application Ser. No. 717,034, filed Mar. 28, 1968, now abandoned, is described a process for simultaneous winning and separating copper and nickel metals. The discoveries underlying the invention in that application are the promotion of copper reduction with carbon monoxide by the presence of nickel carbonyl or manganese carbonyl in an ammoniacal solution and the simultaneous production and separation of nickel carbonyl and copper metal with subsequent extraction of the nickel carbonyl formed into a water-immiscible solvent.

SUMMARY OF THE INVENTION We have now discovered a process for winning nickel which comprises reacting source nickel values with carbon monoxide in the presence of a catalytic quantity of cyanide ion catalyst. Source nickel values contained in sulfide ores, laterite ores, sea nodules, and scrap metal are reacted according to this invention. The reaction may preferably be conducted in a solution or slurry. A most preferred solution or slurry is an aqueous ammonia solution or slurry. Further the process is characterized by conducting the reaction under conditions of elevated temperature and pressure; preferably from about to about 200C and from about 200 to about 2,500 psig. The cyanide ion catalyst can be added in any convenient form at a concentration less than 15 moles of cyanide ion per mole of nickel present.

In addition our invention is capable of winning and separating nickel from the metals commonly associated therewith, such as copper, cobalt, iron, manganese, and the like, both individually and in combinations, such as copper and cobalt formed in a nickel-containing ore.

The reaction can be further characterized by conducting it in the presence of a water-immiscible solvent. A preferred water-immiscible solvent is a saturated hydrocarbon.

A preferred embodiment of the invention is a process for winning nickel metal from a nickel-containing sulfide ore concentrate comprising mixing the concentrate with aqueous ammonia and aerating the mixture to form an ammoniacal solution containing nickel and precipitating iron contained in the concentrate as hydrated iron oxide; contacting the solution with carbon monoxide in the presence of cyanide ion catalyst to form nickel carbonyl; extracting the nickel carbonyl into a water-immiscible solvent; separating the nickel carbonyl from the solvent, and decomposing the nickel carbonyl to obtain nickel metal. Of course, the pressure and temperature conditions, ammonia concentrations, catalyst concentrations and type of solvent used, as well as, other preferred process conditions described above are applicable to the above processMoreover, such a preferred process can be utilized to great advantage to effect the winning and separation of nickel from sulfide ore concentrates containing recoverable amounts of copper, cobalt, and of both copper and cobalt.

DESCRIPTION OF THE PREFERRED EMBODIMENTS By the process of this invention nickel can be obtained from any source nickel values. By the term source nickel values is meant any commercially feasible and economically attractive source of nickel values. That is, any material having a concentration of nickel large enough to be attractive to metal processors may be utilized as a starting material. Thus, it is clear that any naturally occurring ore, processed intermediate thereof, or scrap metal containing nickel is useful in this invention. Typically and traditionally, nickel values contained in naturally occurring ores have been the largest source nickel values considered for producing nickel metal. Such ores as sulfide ores and laterite ores are preferred. However, one advantage of this invention is the wide variety of materials which are amenable to processing. Thus, other source nickel values as sea nodules, scrap metals and the partially processed materials derived from ores; such as, concentrates, mattes, leach solutions, and the like are also preferred. Another nickel-eontaining resource is the waste materials from the physical or chemical concentration of ores processed primarily for their content of other metals; such as, copper, cobalt, iron, manganese, and the like.

According to this invention the source nickel values are reacted with carbon monoxide. The form of carbon monoxide used is not critical. In general, any carbon monoxide-containing gas may be employed conveniently. Without limiting the generality of the foregoing, there may typically be employed water gas, producer gas, Mond gas, synthesis gas, and the like. Preferably a carbon monoxide-containing gas which is solely composed of carbon monoxide and hydrogen is employed, such as synthesis gas. Synthesis gas is a relatively cheap source of carbon monoxide and is preferred for this reason. The partial pressure of hydrogen can vary from zero to 0.8, although preferably the partial pressure of hydrogen is kept below 0.5. A most preferred carbon monoxide-containing gas is pure carbon monoxide. The carbon monoxide pressure utilized is not critical, except that sufficient carbon monoxide pressure to obtain reasonable reaction rates is employed. The carbon monoxide pressure should not be so high as to require unreasonably, expensive high pressure equipment, thus decreasing the economic feasibility of the process. Without limiting the invention, reaction is preferably conducted at elevated pressure, for example, a practical range of pressures employed is from about 200 to about 2,500 psig. Good results are obtained at pressures from about 200 to about 1,200 psig, and this is a more preferable range of carbon monoxide pressures. Most preferably the reaction vessel is maintained at 200 to 400 psig by continuously repressuring the reaction vessel making more carbon monoxide available for reaction with the source nickel values.

It has been found that the reaction of source nickel values with carbon monoxide is greatly facilitated in the presence of a catalytic quantity of cyanide ion catalyst. Any compound producing cyanide ions may be used to introduce the catalytic species. Without limiting the foregoing, such compounds as potassium cyanide, sodium cyanide, hydrogen cyanide, nickel cyanide, and the like are typical sources of cyanide ions. Although it is not required, a convenient means of providing the cyanide ion catalyst is to simply add any of the above cyanide compounds to the reaction vessel in which the reaction is carried out. The order of addition of the reactants and the catalyst is not critical. The cyanide ion concentration conveniently employed is less than about 15 moles of cyanide ion per mole of nickel present. At concentrations greater than this, the use of cyanide ion catalyst presents problems of excessive cost, high losses, and waste disposal. Preferably, the concentration of cyanide ion is from about 0.01 to about moles of cyanide ion per mole of nickel present.

A preferred embodiment of this invention is the reaction of the source nickel values with carbon monoxide in the presence of a catalytic quantity of cyanide ion catalyst wherein the reaction is conducted in a solution or slurry. This can conveniently be done by establishing a solution or slurry of the source nickel values by any art-recognized means of obtaining a solution or slurry of source nickel values. Without limiting the invention, it is common practice to treat source nickel values; for example, an ore, by solubilization, selective leaching, or physical separation of metallic constituents, as for example by flotation, elutriation, tabling, and the like. The amount of source nickel values in the solution or slurry may vary widely according to their origin. For example, this embodiment of the invention may employ dilute solutions, saturated solutions, super-saturated solutions, or slurries of the source nickel values.

The most widely used means of establishing such solutions or slurries is to provide aqueous solutions or slurries of source nickel values. Art recognized methods of doing this, for example, via flotation to physically separate and concentrate source nickel values, are extensively covered in the prior art, see for example Boldt, Jr., (supra), pp. 191-225. Such aqueous solutions and slurries are particularly useful in cases where the source nickel values are water-soluble nickel salts for instance. Other source nickel values which are less amenable to formation of such aqueous solutions and slurries are rendered more soluble by the action of a coordinating agent. A typical and highly preferred coordinating agent for this purpose is ammonia. Thus, it is a preferred embodiment of the invention to employ an aqueous ammonia solution or slurry. Since slurries are also employed, the use of ammonia to solubilize the source nickel values is not considered critical. However, when ammonia is employed, it may be used as a water-containing ammonium salt or as aqueous ammonium hydroxide. Typical ammonium salts useful in this embodiment of the invention are the chloride, carbonate, sulfate, phosphate, bromide, iodide, phosphite, sulfite, cyanide, fluoride, sulfide, and the like including mixtures thereof. More preferred of these are aqueous ammonium hydroxide and the ammonium chloride, carbonate, and sulfate. Most preferred are aqueousammonium hydroxide and ammonium carbonate.

As a result of the use of such ammonium salts, aqueous ammonium hydroxide and even dissolved ammonia gas in the solution or slurry, the concentration of ammonia in the solution or slurry may range up to about moles of ammonia per mole of nickel present. However, beyond such concentrations extreme losses of ammonia affect the economic feasibility. A more practical and preferred range is from about 1 to about 10 moles of ammonia per mole of nickel.

The reaction according to this invention is carried out at a temperature which is sufficient to provide reasonable reaction rates and times. The temperature at which these conditions are met is not critical and any elevated temperature may be used so long as practical considerations of equipment and heating costs are kept within reasonable bounds. Without limiting the invention, temperatures from slightly above room temperature to greater than several hundred degrees may be employed. Preferably the reaction is conducted at a temperature of from about 50 to about 200C. Most preferably the temperature is from about 100 to about 200C.

The time of reaction is not a truly independent variable, but is dependent, at least to some extent, on the process temperature, pressure and use of a catalyst. In general, the reaction time is inversely proportional to the temperature. Usually, reaction times of l to 4 hours are sufficient. Moreover, the addition of a catalytic amount of cyanide ion greatly reduces the reaction time.

The reaction product of the source nickel values with carbon monoxide in the presence of cyanide ion catalyst according to this invention is nickel carbonyl. Nickel carbonyl can be easily decomposed to nickel metal and carbon monoxide which latter material may be recycled to react with more source nickel values. In a preferred embodiment of this invention the nickel carbonyl is extracted from the reaction media, for example an aqueous ammonia solution or slurry, by a water-immiscible solvent for nickel carbonyl. The waterimmiscible solvent is then removed for instance by distillation and the nickel carbonyl decomposed.

As stated above, the nickel carbonyl (prepared by reaction of the ammonia-containing nickel solution and carbon monoxide) is extracted by a water-immiscible solvent forming a second liquid phase. The exact nature of the solvent is not critical as long as it is immiscible with water and dissolves nickel carbonyl and does not react with it. For example, a suitable solvent is a saturated hydrocarbon having a boiling point of from about 50 to about 200C. In a preferred embodiment, a solvent less dense than water is used. Nickel carbonyl is soluble in many organic solvents such as paraffins, mixtures thereof, benzene, and toluene. Preferred solvents are paraffin fractions such as ligroin, gasoline, kerosene, and paraffinic materials such as cyclohexane, hept ane, octane, nonane, etc. Normal or branched chain paraffins can be used as well as mixtures thereof.

The amount of solvent which is used is not critical. It is only necessary to use the amount of solvent required to dissolve the desired amount of nickel carbonyl. There is no real upper limit on the amount of organic solvent this being defined by such considerations as economics, size of reaction vessel, ease of separation of nickel carbonyl therefrom, etc. Generally, from 0.1 to 2 volumes or organic solvent are used per unit volume of aqueous solution. Preferably, from 0.1 to 0.5 volumes are employed.

The nickel carbonyl can be separated from the organic solvent by any method known in the art. As indicated above, distillation is a suitable technique. When distillation is required, there should be as appreciated by askilled practitioner a suitable variance in boiling point between the carbonyl and the solvent. Of course, the boiling point difference required is inversely proportional to the number of theoretical plates in the distillation column. Alternatively, the nickel can be recovered by flashing the solution thereof, above the decomposition temperature of nickel carbonyl.

In a highly preferred embodiment, this invention is a process for winning nickel metal from a nickelcontaining sulfide ore concentrate comprising a. aerating a mixture of said concentrate and aqueous ammonia thereby forming a solution containing said nickel and precipitating iron contained in said concentrate as hydrated iron oxide;

b. contacting said solution with a carbon monoxidecontaining gas at a pressure of from about 200 to about 2,500 psig and at a temperature of from about to about 200C in the presence of a cyanide ion catalyst, forming nickel carbonyl;

c. separating said nickel carbonyl from said solution,

and

d. decomposing said nickel carbonyl to obtain nickel metal.

The process of this embodiment utilizes an ore concentrate from which the desired nickel metal can be produced. Usually, the ore concentrate is derived by known methods from deposits of nickel. Mining nickel usually produces an ore which is unsuitable for further processing until the amount of non-ore containing material removed makes it practical to handle the volumes of metal-bearing ore economically. Separation processes including flotation, elutriation, and filtration remove much of the non-ore bearing material and provide an ore concentrate which is suitable and economi cal for further processing. Their refining methods are well-known and described in texts.

In general, nickel is found together with iron, copper and cobalt as major metal constituents of the ore. Therefore, treatment of such an ore must include the separation of these metals in order to gain the nickel metal as the desired product. The process of this invention is practical for separation of such combinations of metals as cobalt and nickel; copper and nickel; copper, cobalt and nickel; and iron, copper, cobalt, and nickel.

The ore concentrate above is generally derived from a sulfide ore. That is, the metals produced from a mine are in the form of metal sulfides from which the metal values must be derived. While the sulfide ores are preferred in the process of this invention, other ores can also be used after appropriate treatment to convert the naturally found metal values to metal compounds which can be treated by the instant process.

The use of ammonia at a concentration of from about 1.0 to about 10 moles per mole of nickel; preferred carbon monoxide pressures of from about 200 to about 1,200 psig; more preferred cyanide ion catalyst concentrations of from about 0.01 to about 10 moles per mole of nickel present; and a 1 preferred waterimmiscible solvent which is a saturated hydrocarbon having a boiling point of from about 50 to about 200C for this highly preferred embodiment, each form more preferred embodiments of this invention and can be employed therein as described hereinabove.

' Another highly preferred embodiment of this invention is a process wherein copper and nickel present in source nickel values, such as a sulfide ore concentrate are won and separated from both the concentrate and each other. Thus, this highly preferred embodiment is a process for winning copper and nickel in the form of copper metal and nickel carbonyl from a sulfide ore concentrate containing copper, nickel, and iron, said process comprising 1 a. mixing said concentrate with aqueous ammonia;

b. aeratingsaid mixture thereby forming a solution containing said nickel and copper, and precipitating said iron as hydrated iron oxide;

0. contacting said solution with a carbon monoxidecontaining gas at apressure of from about 200 to about 1,200 psig and a temperature of about100 to about 200C in the presence of a catalytic amount of cyanide ion, forming nickel carbonyl and copper metal;

d. extracting said nickel carbonyl into a waterimmiscible solvent; and

e. recovering said copper metal.

The use of ammonia at a concentration of from about 1.0 to about 10 moles per mole of nickel; preferred carbon monoxide pressures of from about 200 to about 1,200 psig; more preferred cyanide ion catalyst concentrations of from about 0.01 to about 10 moles per mole of nickel present; and a preferred waterimmiscible solvent which is a saturated hydrocarbon having a boiling point of from about 50 to about 200C for this highly preferred embodiment, each form more preferred embodiments of this invention and can be employed therein as described hereinabove.

A still further preferred embodiment of this invention treats source nickel values containing copper, cobalt, iron and nickel to win and separate these metals from the concentrate and from each other. Thus, this preferred embodiment is a process for winning nickel in the form of nickel carbonyl from a sulfide ore concentrate containing copper, nickel, iron, and cobalt, said process comprising:

a. mixing said concentrate with aqueous ammonia containing from about 1 to about 10 moles of ammonia for each mole of said copper, nickel, iron, and cobalt present;

b. aerating the mixture thereby forming a solution containing said copper, nickel and cobalt, and precipitating said iron as hydrated iron oxide;

0. removing said hydrated iron oxide from said solution;

. contacting said solution with a carbon monoxidecontaining gas under a carbon monoxide pressure of from about 200 to about 1,200 psig at a temperature of from about 100 to about 200C and in the presence of from about 0.01 to about 10 moles, per mole of said nickel, of a cyanide ion catalyst, forming nickel carbonyl, cobalt tetracarbonyl anion, and copper metal;

e. extracting said nickel carbonyl into a waterimmiscible hydrocarbon solvent in a second liquid phase wherein said hydrocarbon has a boiling point of from about 50 to about 200C;

f. recovering said copper metal from said solution;

g. recovering said nickel carbonyl from said hydrocarbon solvent; and

h. recovering cobalt values from said solution.

The use of ammonia at a concentration of from about 1.0 to about 10 moles per mole of nickel; preferred carbon monoxide pressures of from about 200 to about 1,200 psig; more preferred cyanide ion catalyst concentrations of from about 0.01 to about 10 moles per mole of nickel present; and a preferred waterimmiscible solvent which is a saturated hydrocarbon having a boiling point of from about 50 to about 200C for this highly preferred embodiment, each form more preferred embodiments of this invention and can be employed therein as described hereinabove.

While not desiring to be limited to any particular theory or mechanism of reaction, it is believed that as the source nickel values are put into a solution or slurry they at least partially ionize and can be reduced by the carbon monoxide. As reduction proceeds, nickel ion is reduced and converted to nickel carbonyl. This is soluble in the immiscible solvent. If the treatment is conducted in a two-phase system with a water-immiscible solvent as the second phase, the nickel carbonyl is extracted as it forms out of the aqueous phase into this solvent phase. This layer can be removed, stripped of nickel carbonyl, and recycled to the reactor. The isolated nickel carbonyl can be decomposed to nickel powder. Alternatively, some or all the nickel carbonyl solution can be treated with halogen, for example, bromine in carbon tetrachloride to form nickel bromide.

During the reduction step, copper ion is reduced to the metal and deposited. The copper is removed from the reaction zone. During the reduction step, cobalt cation is reduced to the cobalt tetracarbonyl anion. As such, it can be separated after nickel and copper from the ammoniacal solution by precipitation according to well-known chemical techniques.

After cobalt removal, the aqueous solution contains ammonium sulfate, which is isolated as a by-product. Ammonium sulfate is useful also as a source of ammonia for recycle to form aqueous ammonia in the first step.

The concentration of nickel and copper in this embodiment is not critical. However, it is obvious to a skilled practitioner that it is best to use the process of this invention when the relative amounts of nickel and copper are such that they must be separated in order to obtain acceptable metal product(s). Thus the concentration of copper in the treated solution can vary from very low to saturated concentrations. Similar considerations hold for nickel. Both metals can be in low, high, or intermediate concentrations. Alternatively, there can be considerable variance between their concentrations. In general, the concentration of copper in the treated solutions is preferably 0.001 grams per liter to saturated, more preferably 1 to 30 grams per liter. Similarly, the concentration of nickel is preferably 1 gram per liter to saturated, more preferably 5 to grams per liter.

For best results, the ammoniacal solution, from which the copper and nickel is separated, contains an appreciable amount of ammonia. This substance can be introduced into the aqueous solution by introduction of ammonia gas, or by preparing the solution with aqueous ammonia (NI-1 0B). Preferably, the ammoniacal solution contains from about 1 to about 10 moles of ammonia per each mole of metal in solution. A more preferred range is from about 2 to about 4 moles per each mole of metal.

The copper and nickel can be put into solution prior to their separation by any means known in the art. When putting metal sulfides into solution, it is best to treat the ammonia solution-sulfide mixture with air. Procedures for this are known, and the exact method of aeration is not critical. Typically, air (or oxygen) is pumped into the mixture below the liquid level. The rate of air introduction is not critical. As appreciated by skilled practitioners, the rate (and amount of oxygen) should give a reasonable rate of solution. To facilitate solution, the contents of the vessel should be adequately contacted with air. This is best done, for example, by keeping the sulfides in suspension. The aeration process is preferably carried out under pressure and at high temperatures to assure good yields of metals in solution. Temperatures of about to about F and pressures of about 100 to about 150 psig are preferably employed. This can be followed by a second oxidation at about 400 to about 425F and an air pressure of about 600 to about 725 psig. In this process for putting copper and nickel in solution, excess ammonia is used which is later boiled off or tied up with added acid.

The amount of copper seed used to facilitate copper precipitation is generally from about 0.001 to about 1.0 g/l. Preferably, the amount employed is from about 0.01 to about 0.1 g/l.

Our process can be more fully described by referring to the following examples. All percentages are by weight unless otherwise indicate EXAMPLE 1 To a reaction vessel equipped with a stirrer was added 327 rnillimoles ammonium hydroxide (13.6 molar solution), 54.5 millirnoles NiSO enough water to make a total volume of 100 ml. and then ml. of heptane. The reaction vessel was closed and sealed, pressure lines were connected and the vessel flushed with nitrogen. After pressuring with nitrogen to 60 psig, the autoclave was heated to 150C. on reaching temperature equilibrium, the reaction vessel was pressured further to about 600 psig with carbon monoxide. The reaction was continued for 3 hours. The total pressure drop in the reaction was 235 psi. After rapid cooling, the autoclave was vented.

The organic layer was separated. The amount of nickel carbonyl was determined by decomposition with bromine. The yield of nickel carbonyl was 30 percent. The aqueous phase contained unreacted nickel sulfate corresponding to 51 percent of the amount charged.

The following table shows effect of the addition of cyanide ion in the form of potassium cyanide, K CN. The reaction procedure is substantially the same as in Exarnple 1 above. The various Examples 2-10 illustrate the effectiveness of the addition of a small amount of cyanide ion to the reaction mixture. Further, the catalysis by cyanide ion is not affected to any substantial extent by the presence of other metal ions.

The instant process also produced ammonium sulfate as a by-product. Ammonium sulfate is useful as a chemical intermediate and as a starting material for fertilizer production.

With the above description in mind, a skilled practitioner can perceive other embodiments equivalent to those described herein. Such equivalents are part of this invention. For example, the process of this invention can be carried out using the procedure described hereinabove or any art recognized procedure for obtaining source nickel values when they are derived from a. a laterite 615,

b. an aqueous leach solution of a laterite ore,

c. basic carbonates derived from an aqueous leach solution of a laterite ore,

d. an acid leach solution of a laterite ore,

e. a ferronickel product from a laterite ore,

f. a sulfide ore smelter matte,

g. a sulfide ore converter matte,

h. active nickel granules from a quenched matte,

i. leach solutions derived from scrap metal,

j. comminuted scrap metal, and I k. sea nodules or processed materials derived therefrom. 1

In each of these source nickel values when treated according to our invention, the use of ammonia concentrations of less than about 100 moles per mole of nickel, elevated temperature and pressure, cyanide ion catalyst concentrations of less than about 15 moles per mole of nickel, and a water-immiscible solvent as hereinab'ove described is a preferred embodiment of the invention;

Having fully described the process of this invention, we desire that this invention be limited only by the law- 'TXBLE i Cyanide-Catalyzed Reduction of Nickel, Cobalt, and Copper Sulfates Ex. 2 Ex. 3 Ex. 4 12.1.5 Ex. 6 Ex. 7 Ex. 8 Ex. 9 Ex. 10

Reaction Variables Initial Molar Ratios: N150, 2 9 9 9 110 110 110 110 110 0150, 0.5 12 12 C1180. 27 27 A KCN 1 1 1 1 1 1 1 1 1 Total Pressure Drop, psi. 290 280 305 395 410 I 410 425 400 315 Reaction time hrs. 3.0 3.0 3.0 1.5 2.2 2.2 2.5 3.0 3.0 Duration or gas uptake, hrs. 1.5 1.3 2.2 0.75 1.11 1.8 2.5" 3.0 3.0

R e s u l t s Recovered: N1so,% 14 3.7 8.3 4.8 1.9 1.9 2.4 8.8 30.8 CoSOflG' 74 68.3 74.7 CuSO 37.6 47.2 Conversion to Ni(C0)4,% 39 47 53 90 98 98 94 92 72 Conversion" to-Cu metal,% 63 53 a. fiij nirnoles of NiSO. used in each run. The metal sulfate ammonia ratio was 1:6 All runs were carried out at I and 600 psi initial carbon monoxide pressure. b. Gas was still being taken very slowly when reaetion was stopped.

c. The amount of cobalt found in aqueous solution.

d. Mmoles product found over mmoles of starting metal sulfate.

The copper and'nikel metals obtained as products of the above-described process are useful metals in thetr'iselves for various well-known applications. The nickel carbonyl produced by the process of this application can be thermally decomposed to produce nickel metal powqer. 111 neu or thermal decomposition, the nickel carbonyl may be reacted to form various organonickel compounds useful as nickel plating agents.

in each run. Total volume ofeaeh' run was 100 ml ofaqueous phase and 10 ml of heptane.

Examples 5-10 were repressured three times back r0600 psi.

fill sco peof the appended claims.

We claim:

1. A process for winning nickel metal from a nickelcontaining sulfide ore concentrate comprising:

a. aerating a mixture of said concentrate and aqueous ammonia thereby formin a solution containing said nickel and precipitating 11011 contained in said concentrate as Hydrated iron oxide;

b. contacting said solution with a carbon monoxidecontaining gas at a pressure of from about 200 to about 2,500 psig and a temperature of from about 100 to about 200C in the presence of a cyanide ion catalyst, forming nickel carbonyl;

c. extracting said nickel carbonyl into a waterimmiscible solvent;

d. separating said nickel carbonyl from said solvent;

and

e. decomposing said nickel carbonyl to obtain said nickel metal.

2. A process of claim 1 wherein said ammonia is present in an amount of from about 1.0 to about moles per each mole of nickel.

3. A process of claim 1 wherein said contacting is carried out under a carbon monoxide pressure of from about 200 to about 1,200 psig.

4. A process of claim 3 wherein the concentration of said cyanide ion catalyst is from about 0.01 to about 10 moles per mole of nickel present.

5. A process of claim 1 wherein said contacting is carried out in a two-phase liquid system wherein the second phase is a water-immiscible saturated hydrocarbon solvent for nickel carbonyl, said solvent having a boiling point of from about 50 to about 200C.

6. A process for winning copperand nickel in the form of copper metal and nickel carbonyl from a sulfide ore concentrate containing copper, nickel, and

iron, said process comprising:

d. extracting said nickel carbonyl into a waterimmiscible solvent; and

e. recovering said copper metal.

7. A process of claim 6 wherein said cyanide ion is present at a concentration of from about 0.01 to about 10 moles per mole of nickel present. I

8. A process of claim 7 wherein said solvent is a saturated hydrocarbon having a boiling point of from about 50 to about 200C.

9. A hydrometallurgical process for winning nickel in the form of nickel carbonyl from a sulfide ore concentrate containing copper, nickel, iron, and cobalt, said process comprising:

a. rnixi ng s aid concentrate with aqueous ammonia containing from about 1 to about l0irioles o t 5mmonia for each mole of said copper, nickel, iron, and cobalt present; b. aerating the mixture thereby forming a solution containing said copper, nickel, and cobalt, and precipitating said iron as hydrated iron oxide;

c. removing said hydrated iron oxide from said solution; V

d. contacting said solution with a carbon monoxidecontaining gas under a carbon monoxide pressure of from about 200 to about 1,200 psig at a temperature of from about to about 200C and in the presence of from about 0.01 to about 10 moles, per mole of said nickel, of a cyanide ion catalyst, forming nickel carbonyl, cobalt tetracarbonyl anion, and copper metal;

e. extracting said nickel carbonyl into a waterimmiscible hydrocarbon solvent in a second liquid phase wherein said hydrocarbon has a boiling point of from about 50 to about 200C;

f. recovering said'copper metal from said solution;

g. recovering said nickel carbonyl from said hydrocarbon solvent; and

h. recovering cobalt values from said solution. 

2. A process of claim 1 wherein said ammonia is present in an amount of from about 1.0 to about 10 moles per each mole of nickel.
 3. A process of claim 1 wherein said contacting is carried out under a carbon monoxide pressure of from about 200 to about 1,200 psig.
 4. A process of claim 3 wherein the concentration of said cyanide ion catalyst is from about 0.01 to about 10 moles per mole of nickel present.
 5. A process of claim 1 wherein said contacting is carried out in a two-phase liquid system wherein the second phase is a water-immiscible saturated hydrocarbon solvent for nickel carbonyl, said solvent having a boiling point of from about 50* to about 200*C.
 6. A process for winning copper and nickel in the form of copper metal and nickel carbonyl from a sulfide ore concentrate containing copper, nickel, and iron, said process comprising: a. mixing said concentrate with aqueous ammonia; B. AERATING SAID MIXTURE THEREBY FORMING A SOLUTION CONTAINING SAID NICKEL AND COPPER, AND PRECIPITATING SAID IRON AS HYDRATED IRON OXIDE: c. contacting said solution with a carbon monoxide-containing gas at a pressure of from about 200 to about 1,200 psig and a temperature of about 100* to about 200*C in the presence of a catalytic amount of cyanide ion, forming nickel carbonyl and copper metal; d. extracting said nickel carbonyl into a water-immiscible solvent; and e. recovering said copper metal.
 7. A process of claim 6 wherein said cyanide ion is present at a concentration of from about 0.01 to about 10 moles per mole of nickel present.
 8. A process of claim 7 wherein said solvent is a saturated hydrocarbon having a boiling point of from about 50* to about 200*C.
 9. A hydrometallurgical process for winning nickel in the form of nickel carbonyl from a sulfide ore concentrate containing copper, nickel, iron, and cobalt, said process comprising: a. mixing said concentrate with aqueous ammonia containing from about 1 to about 10 moles of ammonia for each mole of said copper, nickel, iron, and cobalt present; b. aerating the mixture thereby forming a solution containing said copper, nickel, and cobalt, and precipitating said iron as hydrated iron oxide; c. removing said hydrated iron oxide from said solution; d. contacting said solution with a carbon monoxide-containing gas under a carbon monoxide pressure of from about 200 to about 1,200 psig at a temperature of from about 100* to about 200*C and in the presence of from about 0.01 to about 10 moles, per mole of said nickel, of a cyanide ion catalyst, forming nickel carbonyl, cobalt tetracarbonyl anion, and copper metal; e. extracting said nickel carbonyl into a water-immiscible hydrocarbon solvent in a second liquid phase wherein said hydrocarbon has a boiling point of from about 50* to about 200*C; f. recovering said copper metal from said solution; g. recovering said nickel carbonyl from said hydrocarbon solvent; and h. recovering cobalt values from said solution. 